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Drug abuse and addiction can be suspected or diagnosed on the basis of mucosal and cutaneous findings. The administration of drugs may cause cutaneous stigmata and eruptions predominantly through local or systemic, toxic or hypersensitivity-induced effects as a result of the drug itself, adulterants, infectious agents, or the mode of drug delivery.
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Illicit drug use is a maladaptive pattern involving self-administration of prescribed or recreational drugs. Chipping is a lay term used to describe a pattern of drug use in which the user is not physically dependent, but rather sustains “controlled use” of a drug. A certain percentage of users will progress to drug dependence, a physical and/or psychological need for the effects of a chemical in order to avoid withdrawal symptoms associated with abstinence (Box 105-1). Drug dependence often leads to drug abuse, an intense desire to recurrently obtain increasing amounts of one or more chemical substances to the exclusion of all other activities, resulting in clinically significant physical, emotional or social distress (Box 105-2). Tolerance defines a physiologic state in which progressive increases in the dose of a drug are needed to achieve the effects previously experienced at smaller doses. Some drugs chiefly induce physical dependence, while cause predominantly psychological dependence.1
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